#!/usr/bin/perl # Copyright (C) 2000 Mark E. Nielsen at GNUJobs.com # This program is free software; you can redistribute it and/or # modify it under the terms of the GNU General Public License # as published by the Free Software Foundation; either version 2 # of the License, or (at your option) any later version. # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # You should have received a copy of the GNU General Public License # along with this program; if not, write to the Free Software # Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. # Web-Encrypt-Example version 0, Copyright (C) 2000 Mark E. Nielsen at GNUJobs.com # Web-Encrypt-Example comes with ABSOLUTELY NO WARRANTY. # This is free software, and you are welcome # to redistribute it under certain conditions. # The Computer Underground, Inc., hereby disclaims all copyright # interest in the program `Web-Encrypt-Example' # written by Mark E. Nielsen. # Mark E. Nielsen, President of The Computer Underground package MyPackage::Misc; use strict; use Crypt::Blowfish; my $Blowfish_Key = "An extremely dumb password you should change."; my $Blowfish_Cipher = new Crypt::Blowfish $Blowfish_Key; #----------------------------------- sub Encrypt { my $self = shift; my $String = shift; my $Temp = $String; my $Encrypted = ""; while (length $Temp > 0) { ### If less than 8 characters, padd it with tabs while (length $Temp < 8) {$Temp .= "\t";} ### Ecnrypt the 8 length segment my $Temp2 = $Blowfish_Cipher->encrypt(substr($Temp,0,8)); ### Add it to the end $Encrypted .= $Temp2; ### If it is 8 or less, abort, otherwise get the next segment if (length $Temp > 8) {$Temp = substr($Temp,8);} else {$Temp = "";} } my $Unpacked = unpack("H*",$Encrypted); return ($Unpacked); } #-------------------------------- sub Decrypt { my $self = shift; my $String = shift; my $Packed = pack("H*",$String); my $Temp = $Packed; my $Decrypted = ""; while (length $Temp > 0) { my $Temp2 = substr($Temp,0,8); ### In theory, we could up with less than 8 characters, check if (length $Temp2 == 8) { my $Temp3 = $Blowfish_Cipher->decrypt($Temp2); $Decrypted .= $Temp3; } if (length $Temp > 8) {$Temp = substr($Temp,8);} else {$Temp = "";} } ### Getting rid of tabs at the end, which could be a bad thing ### but is how I did it. $Decrypted =~ s/\t+$//g; return ($Decrypted); }

NOTE: There is one special thing you ought to do when decrypting information. Check to see if it contains valid data. If it is numeric, make sure it is a number.Usually a smart idea is to always assume the number is positive and less than a billion, and do something like this,

my $Error = 1;
if (($Value >0) && ($Value < 1000000000)) {$Error = 0;}
if ($Error == 1) {print "Darn it, this sucks, no valid data, bye bye!"; exit;}